In a liquid crystal display device, a liquid crystal is a substance that does not itself radiate light. Instead, the liquid crystal relies on light received from a light source, thereby displaying images and data. In the case of a typical liquid crystal display, a backlight system powered by electricity supplies the needed light.
Typically, there are two types of backlight systems: an edge lighting type and a bottom-lighting type. The edge-lighting type of backlight system is widely used in small and medium size liquid crystal display for merits on small weight, thin body and low energy cost. Large size liquid crystal display seldom uses the edge-lighting backlight system because the results based on the merits mentioned above is poor. Furthermore, the large size edge-lighting type backlight system seldom satisfies the requirement of light brightness and optical uniformity. Nowadays, the market demand for larger size liquid crystal display has increased progressively. Therefore, the bottom-lighting type of backlight system needs to be developed to satisfy the market demand.
A conventional bottom-lighting backlight system includes a thermal module and a light source module. The light source module includes an electronic circuit board and a plurality of light emitting diodes electrically connected to the electric circuit board. The thermal module is generally a flat sheet, which includes a heat conductive surface and a heat dissipating face defined on the opposite surface. The light source module is disposed on the heat conductive surface of the thermal module.
However, adjusting the size of the thermal module of the backlight system cannot be done easily. In addition, because the light source module is fixed to the thermal module, the entire thermal module needs to be disassembled whenever any light emitting diodes on the light source module is damaged. Disassembling the thermal module is very troublesome and also increases the risk of damaging other working elements of the liquid display device.
What is needed, therefore, is a thermal module and a backlight system using the same that overcomes the above mentioned disadvantages.